Connector device



Jan. 2, 1962 E. w. BOLLMEIER CONNECTOR DEVICE Original Filed March l,1955 /M/E/v/Q En. WAYNE 5a ME/E2 p faq V.

United States Patent @tice 3,015,569 CONNECTOR DEVICE Emil WayneBoilmeier, St. Paul, Minn., assignor to Minnesota Mining andManufacturing Company, St. Paul, Minn., a corporation of DelawareOriginal application Mar. 1, 1955, Ser. No. 491,342, now Patent No.2,890,266, dated June 9, 1959. Divided and this application .lune 8,1959, Ser. No. 818,761

6 Claims. (Cl. 2S7--78) jacent mechanical parts. Such connectors areeasily applied, either by hand or by mechanical means, to any of thsusual wire sizes employed in electrical circuitry.

Connector devices illustrating the principles of this invention arefurther described in connection with the drawing, in which:

FIGURE l represents a side elevation, partly in section, of awire-connector including an insulating cover;

FIGURES 2 and 3 are cross-sections of the device of FIGURE l, asindicated; y

FIGURE 4 is a longitudinal cross-section of a modified connector withoutthe insulating cover;

FIGURE 5 represents another modification, partly in section;

FIGURE 6 represents a further modification, partly in section, andFIGURES 7 and 8 represent sectional and rear end views of the article ofFIGURE 6, as indicated;

FIGURES 9 and l0 represent a still further modification7 in partialsection and in end elevation respectively; and

FIGURES 11 and 12 represent details of structures, shown in partialcross-section, which may be employed in place of those of FIGURES 3 and7.

The device of FIGURE 1 includes a tapered tubular helical coil l0 ofspring wire 11 located within a metal shell 12 which is open at theforward end of the coil. The shell 12 is circular in cross-section atthe open end, tapering to a triangular cross-section adjacent theopposite end. The circular cross-section at the-forward end of the metalshell and insulating cover is illustrated at section 2 2 shown in FIGURE2, the corresponding end turn of the coil being omitted for clarity. Thetriangular section at the rearward end of the Wire-connector isillustrated in section 3-3shown in FIGURE 3 of the drawing. The shell 12terminates at the open end in a crimped edge 16, which is eflective inpermanently retaining the Wire coil 10 within the confines of the shell.

The foremost endrturn of the coil 10, which is adjacent the opening inshell 12, khas an external diameter substantially equal to the internaldiameter of the shell at the same area. Subsequent turns of the coil arereduced in diameter, to provide a coil tapered over about one-half itslength and cylindrical over the remaining portion. The rearmost endturnof the coil 1.0 of FIG- URE l has an external diameter equal to thediameter of the largest circle which may be inscribed within thetriangular cross-section of the shell 12 at that point, as illustratedin FIGURE 3; however the end turn may be of any desired smaller diameterin this modification. In-

Patented Jan. 2 1962 termediate turns are less in diameter than requiredto fit snugly within the shell and are therefore capable of expansionwithin the shell. The end of the rearmost turn is extended outwardlyfrom the coil to form a pressure member 35, iitting closely withinl oneof the corners of the triangular end of the shell 12. f

An external insulating sleeve 13 tits over the entire coil and shellassembly. The sleeve 13 terminates in a tubular portion 14 providingaccess to the open end of the metal shell. The material of which thesleeve 13 is made is electrically insulating in character and isliexible and elastic so that the sleeve clings tightly to the shell andso that the terminal tubular portion 14 may conform closely to thesurfaces of the insulated Wires which are to be thrust therein.

As illustrated in FIGURE 4, the shell 42 of this modi- -fication of theconnector is provided with a second axially centered opening at thetriangular end, providing a free axial path through the entirestructure. The device is illustrated without the insulating cover; andin this form it is suitable for making running splices as well asterminal or pigtail splices in electrical conductors and for attachingto wires or rods destined for non-electrical uses. However theinsulating sleeve 13 of FIGURE l may equally well be applied to themodified device of FIG- URE 4, the closed end of the sleeve being thenremoved or opened where it is desired to make a running splice.Alternatively, a tubular elastic insulating member open at both ends maybe employed with the device of FIG- URE 4, or the completed splice maybe'covered with a protective and insulative layer of adhesive tape orcompound. f

In the device of FIGURE 4 some or all of the turns or" the coil 40 areseparated, whereas the turns of coil It) of FIGURE l are contiguous.Coil 4Q is placed Within the shell 42 under axial compression andexpands to fit tightly against the subsequently crimped ends 46 and 47.The end 48 of the wire 41 at the foremost or largest turn is sharp-edgedand digs into the metal of the shell 42., when the latter is turned inthe removal direction, forming an angular recess against which thewire-end presses, thus permitting the removal of the connector from asplice. The coil terminates as in FIGURE 3.

FIGURE 5 represents a modiiication in which the coil 50 is not axiallyexpanded and is shorter than the shell 52, and the forward-most turn ofthe coil is tapered as at 58. When the shell is turned in the removaldirection, the tapered wire slides past the surface of the shell wall,thus preventing removal of the connector once it has been applied inconnecting together a bundle of wires.

The coil 60 of the device of FIGURES 648 is substantially the same ascoil 10 of FIGURE l except that the end portion 65 of the rearmost turndoes not extend as far from the coil as does the pressure member 35shown in FIGURE 3. The shell member 62 of FIGURE 6 likewise is similarat the foremost portion to the shell member 12 of FIGURE l, but diiiersat the rearward portion in being in the form of a small circle havingopposing ns 63 and 64 as indicated in FIGURE 7. The tip 65 of therearmost turn of the coil 60 abuts against one of the corners formed bythe iin 63 in transmitting torque for advancing the unit onto a wiresplice. The fins 63 and 64 are closed at the rearmost ends, and thecorresponding rearmost portion v66 of the shell 62 is crimped over therearmost turn of the coil 60, as indicated in FIGURE 8.

The two-part telescoped shell 92 of the device of FIG- URES 9 and 1G isin hexagonal form, this modification being designed for application witha wrench. The device is useful as a wire-connector, and may also be usedas a self-locking nut on threaded rods or the like. The coil springcompression member is normally axially extended, and is inserted withinthe shell 92 under compression as the two halves of the shell arepermanently forced together. The two end turns of the coil 90 will beseen to be of substantially identical diameter, the coil tapering to asmaller diameter at the central turns. Each of the endsof the shell isslotted as at 91 and the slotted portions upset as at 93 to produceinternal angular recesses having sides against which the tips 95 of thehelix 90 may press. Since the same construction exists at both ends ofthe connector, the latter may be applied and sub sequently removed asdesired. rifhe radially contracting spring maintains the connector infirmly attached relationship to the wire-bundle or rod over which it isapplied, until external ltorque is applied for removal.

Grooves or indentations 111 in the cylindrical shell 112 in FGURE llprovide an altcrnative type of angular recess for transmitting torquefrom the shell to the coil 110 through the wire-end 115. In thisstructure, as in FIGURE 9, both end turns may be of the same diameter,and the wireend is not extended. The structure is also applicable tocoils having a smaller rearmost turn and contained in a tapered conicalshell. A ribbed or fluted insulating cover may be placed over the metalshell if desired.

The rearmost turn of the coil 120 of FIGURE 12 is in the form of atriangle fitting snugly within the end portion of the shell 122., whichcorresponds to the shell 12 of PEG-URE 3. The tip of the wire 121 ishere turned inward, rather than outward as in FIGURE 3, and bearsagainst the ends of an inserted wire-bundle to indicate a `completedinstallation. The triangular form of the terminal turn provides foreffective torque transmission without distortion of the shell such as issometimes caused by the protruding wire-end 35 of FIGURE 3 or thewireend 65 of FIGURE 7 under excessive torque.

In operation in the splicing of insulated copper conductors, using theconnector of FIGURE l, the tips of the conductors are first freed ofinsulation and are bundled or lightly twisted together. The bundle ofwires is then pushed into the open end of the wire-connector, throughthe tubular portion 14 of the sleeve 13 and through the open end of theshell 112, while the entire connector is rotated. The angular shape ofthe rearward portion of the shell serves to provide an effective gripfor manual or mechanical rotation of the connector and also serves totransmit the rotating movement to the coil by way of the pressure member35. Pressure of the wire-ends against the interior or" the spring wirecoil 10,

combining with the rotating movement of the coil, causes the centralturns of the coil to expand under tension and to grip the wire-ends,with the result that the coil is screwed onto the wire-ends to form acompact and permanent splice. Electrical contact between the wire-endsand mechanical stability of the entire splice is permanently maintained,even under extreme intermittent tension and vibration, due to the highcompression provided by the expanded spring wire coil. The fiexible coilis protected from deformation by the trough metal shell 12, which alsoserves as a smooth uniform base for the flexible elastic insulatingcover. The insulating cover provides effective electrical insulation forthe entire assembly; but this component of the structure is not reliedupon either for mechanical protection of the connection or formechanical advantage in the application of the device to the wire-ends.The entire structure is neat in appearance, having smooth contours andfitting tightly to the insulated portion of the wires.

A given size connector permits the connecting of a wide range of sizesand numbers of wires. For any given splice, a connector should beselected in which the helical coil has an entrance opening capable ofaccepting the bundlel of wire-ends and tapers to a diametersubstantially less than that of a circle just capable of containing thebundle of wire-ends.

Application of the connector to wire splices may be accomplished eitherby hand or by mechanical operations. The shape of the wire-connector issuch that the device may be easily applied and twisted with the lingers,or may readily be temporarily fitted into a suitably shaped socket in aspeed wrench, thereby mechanically to provide the necessary twistingtorque required for the appli# cation of the connector to the bundle ofwire-ends.

The wire-oonnector of this invention is particularly adapted for formingend or pigtail splices between small `copper wires. It may, however, beemployed with much larger copper or other metallic conductors or withwires or rods employed for other than electrical purposes.

Particularly for high speed mechanical application the connectorsillustrated in FIGURE l may be provided in the form of a continuous baror coil, with the sleeve 14 of each following connector engaging thetriangular tip of the preceding connector. The har thus formed is fedinto the applicator, each foremost member being removed and rotated ontosuccessive wire-bundles.

The connectors of this invention may be pre-filled with insulating orprotecting pastes or other flowable plastic material. Silicone greases,mineral oil greases, soft and plastic rubbery butadiene-styrenepolymers, and other materials of analogous physical properties areuseful. The inclusion of powdered zinc or aluminumA in such compositionsis of assistance in providing improved electrical contact, particularlyin the case of oxide-coated aluminum wires. The adherent greasy plasticmaterial fills all voids around the conductor terminals and affordsimproved mechanical, chemical and electrical protection to thewire-splice. Softer materials may be retained within the connector bylightly sealing over the open end or ends, e.g. with hardened wax orwith a thin membrane of the same composition as the insulating sleeve.

The several structures described andvillustrated, and other analogousmodifications, may obviously be combined in other ways to provideadditional specific but non-limiting structures and examples. f

What is claimed is as follows:

kl. A connector device capable of being threadably axially advanced overa wire or rod-like member to provide a firm compression grip thereon andcomprising a tapered helical spring-wire fastening element and a rigidcover member centrally open at each end, said fastening element beingretained within said cover member and having end turns fitting snuglywithin the corresponding ends of said cover member and havingintermediate turns of a diameter less than the internal diameter of saidcover member and expandable under spring tension as said connectordevice is advanced over said wire or rod-like member, said end turnsterminating in wire-tips accessibly located for application of forcethereagainst in threadably rotating said fastening ele-ment, said rigidcover member being provided at each end with a single inwardly extendingprojection for bearing against the corresponding wire-tip intransmitting torque from said cover member to said fastening element.

2. A connector device capable of being threadably axially advanced overa wire or rod-like member to provide a firm compression grip thereon andcomprising a tapered helical spring-wire fastening element and a rigidcover member centrally open atleast at the forward end and having asingle inwardly extending projection at least at the rearward end, saidhelical element being retained within said Vcover member and having aforemost turn snugly fitting within the forwardv section of said covermember, a rearmost turn snugly fitting within the rearward section andwith the wire-tip in position for torquetransmitting pressure-contactwith said projection, and a plurality of intermediate turns of adiameter less than the corresponding internal diameter of said covermemberv and expandable under spring tension as said conductor device isadvanced over said wire or rod-like member.

3. A wire-connector comprising: a spring-wire helix having a pluralityof convolutions providing a forward opening of enlarged diameter adaptedto receive a wirebundle, a medial portion of substantial length having abore of reduced diameter and expandable under spring tension produced onthreadably advancing said helix onto a said wire-bundle, and a rearwardend turn terminating arcuately in an end abutment; and a sheet-metalShield encasing said helix in endwise compressive peripheral contact atthe forward and rearward ends of said helix and having spaced clearancewith said medial portion of Said helix for permitting expansion thereof,said shield having an internally extending projection lying in thearcuate path of said end abutment for engagement therewith intransmitting torque from said shield to said helix during threadableadvance of said wire-connector.

4. Al wire-connector comprising: a plurality of convolutions ofspring-wire forming a tapered continuous helix having a forwardopeningof enlarged diameter adapted to receive a wire-bundle, a medial portionof which at least a substantial segment has a bore of reduced diameterand is expandable into threaded gripping relation about a wire-bundleinserted through said forward opening, and a trailing last convolutionterminating arcuately in an end abutment; and a sheet-metal shieldhaving a forward and a rearward inwardly shouldered opening encasingsaid helix in retaining endwise contact and having spaced clearance withthe reduced-diameter medial portion of said helix, and said shieldhaving an internally extending projection lying in the arcuate path ofsaid end abutment for engagement therewith in transmitting torque fromSaid shield to said helix during threadable advance of saidwire-connector along said wire-bundle.

5. A wire connector comprising: a plurality of convolutions ofcontinuous spring wire formed into a helix having forward and rearwardopenings of enlarged diameter and having for a substantial portion ofits medial length a bore of reduced diameter adapted to be expanded intothreaded gripping relation about a wirebundle inserted at either of saidopenings, said helix having a leading rst convolution and a trailinglast convolution each terminating arcuately in an end abutment; and asheet metal shield having both a forward and a rearward inwardlyshouldered opening encasing the helix in retaining endwise contact andhaving spaced clearance therewith at the medial portion thereof, saidshield having an internal offset abutment lying in the arcuate path ofthe end abutment of each of said rst and last convoluticns fortransmitting torque from said shield to said helix in either direction.

y6. A spring-connector comprising a plurality of convolutions ofcontinuous spring-wire forming a helix having terminal openings ofenlarged diameter and having for a substantial portion of its mediallength a bore of reduced diameter adapted to be expanded against theresiliency of the medial convolutionsfof said helix and including alea-ding rst convolution and a trailing last con- Volution eachterminating arcuately in an end abutment; and a hexagonally contouredsheet metal shield having both a forward and a rearward inwardlyshouldered opening accessibly encasing said helix in retaining endwisecontact and having spaced clearance therewith at said medialconvolutions to permit resilient expansion thereof and having aninternal offset abutment lying in the arcuate path of the end abutmentof each of said first and last convolutions for transmitting torque fromsaid shield to said helix in either direction.

References Cited in the file of this patent UNITED STATES PATENTS704,869 Fischer et al. July 15, 1902 1,657,253 Fortin Jan. 24, 19281,830,920 Sundh Nov. 10, 1931 2,022,946 Steampli Dec. 3, 1935 2,792,560Bollemeier May 14, 1957 2,861,826 Schinske Nov. 25, 1958 FOREIGN PATENTS678,944 Great Britain Sept. 10, 1952

